Ask the Coaches: Treadmill Running

Q: Coach,How does running on a treadmill differ, in terms of biomechanics, from running on terra firma?How does one compare treadmill workouts to workouts on the track? –Thanks.

A: Dear Indoor Runner,

I suspect that the treadmill is more biomechanically forgiving than terra firma. First, it seems to me that no one on a treadmill is ever guilty of overstriding (ie, footstrike occurring back on the edge of the heel while there is still several inches of space between ground and the front of the shoe with the knee locked and the leg straight). There is a smoother, lighter footstrike because of the moving belt pulling the foot closer under the center of gravity as the shoe comes into full contact with the surface. Then there is the trampoline effect of the board under the belt so there is less shock upon weightbearing. Finally, the belt almost throws the back leg up into the air at toe off.

I wish I had a really specific answer for you for comparing track workouts with treadmill running. However, no one I know has come up with a definitive way of determining the correlation of effort and speed between treadmill and outdoor running. I personally always have the perception that I'm running a lot faster on the treadmill than the speedometer indicates. I'm sure that if I could jump off a treadmill going at 8 mph and run at exactly that same pace and effort around a 400 m track I would be running at much faster than 7:30 pace. Just a funny perception, I guess.

To make treadmill workouts require the same effort as running on any kind of flat, hard surface, there seems to be a consensus that the treadmill should have about 1 degree of inclination. Despite that "correction," I have had a hard time getting heart rates to match up at similar paces. There are many reasons for this, which are debated endlessly by us locker-room lawyers, but suffice to say, not all of your training should be on a treadmill if you expect to race on the roads.

Sorry to be so vague, but that's my story and I have to stick with it.